Water pump replacement - difficult??

[jameshoward]

Evening All,

I have a strange sound coming from the front of the car. On investigation, I found that the radiator fan had a degree of lateral play and when manipulated, small drips of water came out from the spindle on the pump. I am assuming I need a new water pump and have ordered one from SLS for 70 euros.

Questions: Is this a difficult job? Are there any things to watch out for, and do I have to remove the radiator to do it? (I've only replaced it with a re-core about 5 months ago). Is it better to remove the pump with the fan and viscous coupling attached, or better to remove the rad then the fan, then the pump? If that is the correct order, how does one remove the fan from the viscous coupling?

I've done a search on the water pump, and whilst there is a lot on cooling, could not find a thread on how it is repalced.

All advice gratefully received. Thanks.

JH

[waqas]

quote:Originally posted by jameshoward

Questions: Is this a difficult job?

Pretty straightforward, actually.

quote:Are there any things to watch out for, and do I have to remove the radiator to do it? (I've only replaced it with a re-core about 5 months ago).

Just remember to use thread sealant on the bolts attaching the pump to the housing, as the bolt holes directly access water passages.

You don't necessarily have to remove the radiator. The radiator mounting holes are slotted, so you can loosen the bolts and slide the rad. forward. This should give you enough space to remove the fan/coupling assembly. However, mine doesn't give me enough room so I end up having to drop the radiator (drop instead of lift, so hood does not get involved).

quote:
Is it better to remove the pump with the fan and viscous coupling attached, or better to remove the rad then the fan, then the pump? If that is the correct order, how does one remove the fan from the viscous coupling?

You would first slide or remove the radiator, then remove the fan/viscous-coupling assembly from the pump/pulley assembly. Finally, the pump can be replaced (the pulley is just placed there).

If you need to replace the viscous coupling, I would disassemble the fan/coupling assembly on the bench.

Be sure to replace the pump gasket (should come with the pump kit). When I did this job, I just ended up replacing all hoses and gaskets in the area (pump housing to block gaskets, banjo bolts, washers and little c-shaped metal water line, thermostat, and little elbow-shaped water hose below thermostat housing).

[waqas]

Thought I'd add some more information.

My problem of "strange noises" similar to yours:
http://index.php?topic=5763

I once had questions about short-hub vs. long-hub water pumps:
http://index.php?topic=6464

In case you decide to remove the water-pump housing in order to replace gaskets, etc:
http://index.php?topic=6758

I would replace the coolant bypass hose whilst you have this area apart:
http://index.php?topic=7641

[jeffc280sl]

James,

You need to remove the belts.  There are four 10mm ( I think?) bolts holding the fan to the water pump shaft.  They are a pain to take off and put back. No way around it that I know of.   A long and thin, not common, 10mm wrench is best for the job.  I suppose it is a little easier if the radiator is removed but not much.

While in there you should replace the short hoses connected to the thermostat housing.  One hose goes to the water pump and it is a great time to do this job.  If you have A/C it is a good time to replace the bearing on the idler pully.  Once you have the pully off you can read the standard bearing numbers and buy the bearing at your local shop.

Also a good time to clean the front of the engine, check the power steering pump and hoses etc.

[ja17]

Hello James,

Some tips; I use a long handle 10mm wrench (the box end) to break these bolts loose. It is a Snap-on and the box end is skinny enough to fit in the tight quarters. Leave the belts on this will keep the fan from spinning while your loosening the bolts. Pushing down on the belt with the other hand will keep the fan from turning while your working on loosening the bolt. Using the wrench you can bring each of the four bolts to the top by allowing the fan to turn then push down on the belt and loosen the bolt. Once the bolts are loose you can use the open end of the wrench to finish removal. Loosen all four bolts several turns before you start removing them. You can leave the last bolt half in and just slide the fan off of it. During re-assembly use this trick to keep the pulley in alignment with the bolt holes (start one bolt before installing the fan blade).  As mentioned, the fan clutch is left bolted to its fan blade. Store the fan blade and clutch vertical to prevent loss of fluid. The only thing which makes the job much easier is hood removal.

[jameshoward]

Joe, Jeff, Waqas,

Thanks for the advice. The pump arrived today although the gasket was annoyingly broken. I will make one from card. I will try to do it without removing the radiator as the consensus seems to be that it's possible without so doing. I assume I have to drain off some coolant first given that the pump is coming off.

Joe - excuse the stupid question, as I'm sure it's clear to every other reader, but are your directions for the removal of the fan blade and viscous coupling prior to removal of the pump, or do I remove the whole assembley before splitting it into the pump part and fan part?

Thank you all once again. It's a job for the weekend if I can bear it!

JH

[jeffc280sl]

James,

Can't speak for Joe but I believe it is near impossible to remove the pump and fan as an assembly.  I think the recommendations are to loosen the fan bolts while the belts are still connected to prevent movement.  Then reduce radiator level and remove belts. Then you can get at the pump.

Good luck!

[ja17]

Hello James,

The only stupid question is the one not asked!  Yes, Jeff is correct. remove the blade and clutch as a unit, then move on to thepump bolts.  Drain the coolant by loosening the lower radiator hose. The radiator drain plug is quite often stuck and using it can result in damaging the lower radiator tank!

[jameshoward]

Gentlemen,

I have the water pump, but on inspection it seems that I may have been sent the incorrect pump. From what I can see, my pump has 4 bolts equally spaced attaching it to the fan assembley and as mentioned in the posts below. (See my photo of the existing pump). However, the one I have been sent has only 3 holes (see photo). Can anyone shed any light on this? I gave SLS my engine number so they should have sent me the correct item.

It's my opinion that I have the wrong pump, but before I send it back and order another, I just thought I'd ask for a second and better informed opinion!

Thanks,

James


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[J. Huber]

Hey James, what model/year car do you have?

I replaced my water pump last Fall (had it done -- but I supplied parts). I know there are more than one style of pump for the 280 -- but I think for the 230SL, there is only one. The one I ordered was from K & K.

Model number: 115 200 1220   (not sure if that # would be universal or just for them) My old one had three holes as did new one.

I also replaced the gasket to the water pump, the water line tube & bolts. The gasket from water pump to block, and the gasket from thermostat Hsg. to the head. Thermostat, upper and lower hoses and that little cooling hose by thermostat.

[waqas]

The pump you received is correct for a 230SL: it did not have a fan with viscous coupling. If you want to continue using the viscous coupling, then you'll need a pump from a later car (250SL/280SL) which has the four bolts like your current pump.

The fan in a 230SL has 4 blades and is bolted on directly to the water pump with three bolts. The original 230SL fan was some kind of metal alloy, whilst replacements are white plastic.

Whenever the switch was made to the viscous coupling, the fan was made out of metal and now had 6 blades. The viscous coupling was what was actually bolted on to the water pump now using 4 bolts. This setup is all I've ever seen in 250SL and 280SL cars.

[J. Huber]

All good info Waqas -- except I believe the earlier 230SLs also originally had the plastic fan. (as chincy as that sounds -- it is a very thick durable plastic!)...

[jacovdw]

James,

My early 1964 SL has a metal 4 blade fan. Even the fintail sedans of the same era had the metal fans. As Waqas pointed out, the replacements are made of a white plastic (that also turns a dirty yellow with age).

The viscous coupling only featured in the 250 and 280SL's. It was never originally fitted to the 230SL's.

[waqas]

quote:Originally posted by J. Huber

All good info Waqas -- except I believe the earlier 230SLs also originally had the plastic fan. (as chincy as that sounds -- it is a very thick durable plastic!)...

I think you're correct. In fact, I just checked and the plastic fan 180 205 09 06 is listed in my parts book as the standard  setup, whilst two optional fans are listed as 108 205 03 06 and 108 205 04 06. These latter two numbers are obviously from the sedan series, and might correspond to the metal fan. I wonder what advantage the metal fan would have provided?

[Naj ✝︎]

quote:Originally posted by J. Huber

All good info Waqas -- except I believe the earlier 230SLs also originally had the plastic fan. (as chincy as that sounds -- it is a very thick durable plastic!)...

Like this one?

http://www.sl113.org/forums/uploaded/tempur/20086113466_DSC01080.JPG

[waqas]

As I'm in the midst of clearing my 230SL engine bay right now (just removed the engine yesterday), I actually have a full set of each type of fan to compare. I'll try to post some pics sometime soon.

[jameshoward]

Many thanks for your posts; very useful.

I have now ordered the correct (but technically wrong) water pump. I was wondering, given that I have a 230SL with a 2.3L engine, some PO at sometime must have decided that the car needed the viscous coupling or put in a 2.3l engine that already had one. Question: could I delete the fan clutch and return to the original and correct configuration by simply buying a new fan and then changing the car back to the original 3 screw water pump? What would be the effect of deleting the fan clutch?

On a related matter, I noticed that the cowling fitted to the radiator - which my car has - seems to be only fitted to cars shipped to the US. If you look closely at the 3 SLS pages that deal with radiators and cooling, the cowling has 'USA' written on it. I assume this means it was only fitted to US cars. I've never noticed that before. I suppose they did this because the climate is so much hotter given that the cowling makes quite a difference to the cooling effect.

JH

[waqas]

quote:Originally posted by jameshoward

I have now ordered the correct (but technically wrong) water pump. I was wondering, given that I have a 230SL with a 2.3L engine, some PO at sometime must have decided that the car needed the viscous coupling or put in a 2.3l engine that already had one. Question: could I delete the fan clutch and return to the original and correct configuration by simply buying a new fan and then changing the car back to the original 3 screw water pump?

Yes, it would be simple to switch back to the original setup by replacing the fan and the pump.

quote:What would be the effect of deleting the fan clutch?

When the clutch is engaged, the effect should be similar (pros: more fan blades, so perhaps more CFM; cons: heavier fan to move by the engine).

When the clutch is disengaged, the effect would be better (pros: less drag on the engine as fan is not completely driven).

In the stock 230SL setup, the fan always turns with the engine regardless of temperature.

Personally, I'd just leave it as is if everything works. (unless you are concerned about originality)

quote:On a related matter, I noticed that the cowling fitted to the radiator - which my car has - seems to be only fitted to cars shipped to the US. If you look closely at the 3 SLS pages that deal with radiators and cooling, the cowling has 'USA' written on it. I assume this means it was only fitted to US cars. I've never noticed that before. I suppose they did this because the climate is so much hotter given that the cowling makes quite a difference to the cooling effect.

The cowling was never fitted on the 230SL cars. I don't know about the differences between US/European delivery, but I think it was added when the fan was changed over from the one-piece to the two-piece setup (fan and viscous fan clutch).

[jameshoward]

Waqas,

Yep, I agree the SLS only shows the cowling on the 280 engine. As for the clutch, my fan always turns regardless of temp. It may be that it just spins gently, although it looks pretty fast. I am not convinced that the coupling works, though you can spin the fan pretty easily by hand when the engine has stopped. Who knows. Anyway, I believe I will leave things as they are and just get the right wrong water pump.

Thanks again.

James

[waqas]

As promised, here are pictures comparing the three types of fans (front and back): plastic 230SL fan (4-blade), metal 230SL fan (4-blade) and metal 250SL/280SL fan (6-blade).

Normally one shouldn't store the viscous coupling horizontally, but I've no intention of reusing this one.

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The plastic 230SL fan has the part number 180 205 09 06 cast in the centre hub. The 250SL/280SL 6-blade fan has the part number 108 205 10 06 cast in the centre hub. I couldn't find any part numbers on the metal 230SL 4-blade fan.

Also, notice the four bolts on the back of the 6-blade fan that hold the fan onto the viscous coupling.

[hands_aus]

Notice how the 6 blades are not symetrically spaced around the hub.